Mechanisms of chondrocyte adhesion to cartilage: role of β1‐integrins, CD44, and annexin V

Abstract

The initial adhesion of transplanted chondrocytes to surrounding host cartilage may be important in the repair of articular defects. Adhesion may position cells to secrete molecules that fill the defect and integrate repair tissue with host tissue. While chondrocytes are known to become increasingly adherent to cartilage with time, the molecular basis for this is unknown. The objective of this study was to investigate the role of (31-integrin, CD44, and annexin V receptors in chondrocyte adhesion to cartilage. Chondrocytes were cultured in high density monolayer, released with trypsin, and allowed to recover in suspension for 2 h at 37°C. Under these conditions, flow cytometry analysis showed that chondrocytes expressed (31-integrins, CD44, and annexin V. In a rapid screening assay to assess chondrocyte adhesion to cartilage, cell detachment decreased from 79% at 10 min following transplantation to 10% at 320 min. Treatment of cells with a monoclonal antibody to block p1-integrins significantly increased chondrocyte detachment from cartilage compared to untreated controls. Similarly, results from a parallel-plate shear flow adhesion assay showed that blocking Dl -integrins significantly increased chondrocyte detachment from cartilage compared to untreated controls at each level of applied shear (0-70 Pa). In both assays, treatment of cells with reagents that block CD44 (hyaluronan oligosaccharides or monoclonal Ab IM7) or annexin V (polyclonal Ab #8958) had no detectable effect on adhesion. With cartilage treated with chondroitinase ABC, blocking pl -integrins also increased chondrocyte detachment, while blocking CD44 and annexin V also had no detectable effect. Under the conditions studied here, 01-integrins appear to mediate chondrocyte adhesion to a cut cartilage surface. Delineation of the mechanisms of adhesion may have clinical implications by allowing cell manipulations or matrix treatments to enhance chondrocyte adhesion and retention at a defect site.

Adhesion of perichondrial cells to a polylactic acid scaffold

“…Low adhesion of chondrogenic cells to a substrate is expected at early stages after cell seeding [24,28]. We found that less than half of the seeded cells attached to the PLA scaffold, consistent with a previous study [27], and that a large number of cells were present on the incubation plates after one day of culture.…”

Cathepsins B, K, and L Are Regulated by a Defined Collagen Type II Peptide via Activation of Classical Protein Kinase C and p38 MAP Kinase in Articular Chondrocytes

“…Upon binding, the calcium influx into chondrocytes is significantly stimulated (37). Second, there are some reports dealing with the interaction of annexin V and integrins (39,54). The interaction between FIGURE 6.…”

Synthesis of proteoglycan 4 by chondrocyte subpopulations in cartilage explants, monolayer cultures, and resurfaced cartilage cultures

“…These layers of cartilage were either punched into smaller, 3.5-mm-diameter discs or used for cell isolation. Isolated chondrocytes were obtained by sequential enzymatic digestion (with 0.2% Pronase and 0.02% collagenase) of the cartilage slices from the 3 zones (32).…”